The guidelines were sent to the government yesterday as the House of Commons science and technology select committee wrote to home secretary Alan Johnson demanding a full account of why he dismissed Nutt from the chairmanship of the Advisory Council on the Misuse of Drugs (ACMD).

More than 20 academics drafted the guidelines that they say "would enhance confidence in the scientific advisory system and help government to secure essential advice". Signatories include the former chief of the Medical Research Council Colin Blakemore, former government chief scientist Robert May, the president of the Royal Society Martin Rees and the director of the Science Museum Chris Rapley. In addition, there are chairs and other members of independent scientific advisory committees and the heads of several academic and research bodies.

The guidelines argue that "disagreement with government policy and the public articulation and discussion of relevant evidence and issues by members of advisory committees can not be grounds for criticism or dismissal."

When scientific advice is rejected, the experts said, the reasons should be described explicitly and publicly.

"The priority now must be to rebuild the confidence of the scientific community in the way the government, and indeed the opposition parties, treat scientific advice and those who provide it," said Blakemore. "If the government can sign up to this statement, which essentially summarises commitments that have been made in the past, I hope that we can press the 'reset' button on the relationship."

Liberal Democrat MP and science spokesperson Evan Harris proposed the idea of the guidelines in response to what he called the "unfair" treatment of Nutt. "The discontent in the scientific community about the treatment of David Nutt goes way beyond the members of the ACMD. It is necessary that the government reflects on the recent select committee report, which covers many of the issues set out in the statement in order to win back the full confidence of their unpaid independent expert advisers."

Nutt's sacking came just days after the government supported the independence of scientific advisers in its official response to an inquiry by the House of Commons science and technology select committee into the use of scientific advice in government.

In its report, the committee said scientists should not be criticised for publishing scientific papers or making statements as professionals, independent of their role as government advisers, and that "it is important to safeguard the independence of the [science] advisory system. In situations where the independence of a [science advisory council] chairman or member is or might be threatened for political reasons, support should be offered by the DCSA [departmental chief scientific adviser] and/or the GCSA [government's chief scientific adviser]".

In his letter to Alan Johnson, Lib Dem MP Phil Willis, the chair of the science and technology committee, asked the home secretary to explain what force remained in the assurances given by the government. He also questioned whether the ACMD still had the expertise needed to carry out its duties, given the loss of three of its experts.

Tracey Brown of pro-science campaign group Sense About Science said the scientists' new guidelines would promote much-needed clarity about what "independent scientific advice" meant. "In order for this huge unpaid effort from the scientific community to continue, everyone needs to be clear that independent scientific advice can be neither a substitute for policy nor subject to policy."

After Nutt's dismissal, the Home Office said that it had already started a review of the functions of the ACMD and whether it represented good value for money.